Commodore PR-100

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Calculators: Handheld: Commodore PR-100 type II (aka PR100, PR 100)

		Size (approx):	77.5mm (max) x 158mm x 31mm (max) (w,h,d) Weight 210g including internal batteries
		Power:	Internal rechargeable batteries. Use adaptor 640, 707, 708 or 709 through a socket on the top side to the far left. I found 4.5V centre positive worked OK. Charge time is quoted as three hours - which gives 2-3 hours usage.
		Case:	Two-piece stippled chocolate-brown plastic case. The keys in chocolate brown, light brown, caramel and white are an unusual departure from the normal commodore primary colours. The dark brown keys are actually flecked with gold colouring. They have a loose with soft click action. Above each key is an extra function label, raised and painted gold. The red plastic display filter is flat, slightly raised and lightly tilted. High magnification of the display gives a large image, but very limited viewing angle for the digits.
		Display:	12 digit red LED with bubble lens: 8+2 scientific mode with two extra digits for negative and error indication.
		Features:	Standard four functions, square root, reciprocal, pi, squares, factorial (including permutations and combinations), sign change, percentages, conversions, register exchange, integer, parenthesis (4), six function memory, trig and transcendental functions, DRG, statistics and graphical functions, sexagesimal base (HMS rather than DMS), fixed decimal mode, engineering mode, ten memories and fractions. Programmable: 72 steps, ten registers..
		Age:	1977-8
		Manufacturer:	Commodore Electronic Calculators. Made in England. Serial No. 170916
		Comments:	There are two case versions of this calculator, one that is more like the P50, and this boxy looking one that may be specific to Europe - and there are suggestions that it was the used for release to OEMs. Unusual departure from the normal shaped Commodore calculators. The functions are considerable but the lack of recovery is annoying, as is the default 2 fixed decimal mode. The example on the left is missing its lower edge Commodore label, brown printed in gold.

Components:	Not examined
Boards:	Not examined
Construction:	Remove the two screws from the back and the back section should lift off easily, hinging from the bottom.

Logic comments:	(C/CE) is used once to cancel the last number entered and a second time to clear the whole calculator (CA) will clear all working registers
	Input overflow is suppressed, inputting a ninth digit is ignored
	There is automatic constant on all four functions
	Negative numbers are shown with a "-" in the far left (twelfth) digit thereby allowing full eight digit negative numbers
	The change sign can be used in mid number entry, even for the exponent
	Overflow shows tall-"r" (or if negative "F") in the far left (twelfth) digit and is not recoverable
	Divide by zero just shows tall "r" in the far left (twelfth) digit with "0." in the mantissa and is not recoverable
	Negative square roots are not allowed and result in an overflow with the answer which is not recoverable
	Use the memory with (M)(#) to store, (MR)(#) to recall, etc where # = 0-9
	There is no indication of memory store - you have to remember it
	There is a three way switch to go between Clear, Run and Load modes for programming
	To set a particular number of fixed decimal points use (F)(FP)(#) where # is 0-7, at switch on it defaults to two digits
	Display in engineering (with a fixed decimal of #) will display 3+# digits in the mantissa plus an exponent showing the nearest power of three - which may be used to show answers in standard units, e.g. milliamps, microamps etc
	Display in scientific mode is eight mantissa and two exponent with two extra digits for negative indication. Internal precision is 10 digits: i.e. (pi)(-)(3)(.)(1)(4)(1)(5)(9)(2)(7)(=) "-4.6 x 10^-8"

	Enormous box to accommodate not just the calculator but the adaptor as well. It measures 94mm x 240mm x 60mm (w,h,d) and must have originally had an inner former to withstand the weight of all the stuff. Printed in four spot-colour with half-tone Minuteman logo. I love the way they call it a "Personal Mini Computer" - PET here we come! The reverse just has the red and blue "Commodore ribband", whilst one side has the same strap line. One end has a stamped PR100 model number but no serial number, the other (on my example) has a sticker with ref No. W26 03 6462 2 - which may be a retailer's stock number. Ref: 400169-01.		The chunky, but small manual measures 84mm x 148mm x 7mm. It is printed in one colour black with a half-toned grey Commodore name on the front page. Glued spine construction. It is paged numbered up to page 55, when the programme library starts - another 56 printed pages - phew! My example has an (single sided) Errata Sheet for page 45. Ref: 414023-01 Rev.A Ref: 201393-01 Rev.B Jan 1978 (good grief that means they already revised it due to problems and still had to include an erratum sheet!) Extensive instructions and library, it also includes a four page Guarantee slip printed in blue in English, German and French. Ref: 414024-04 REV B
Quote from manual's opening page: "Thank you for selecting our new scientific programmable calculator. The Commodore PR 100 is one of a powerful range of advanced machines and is virtually three calculators in one. Firstly, it comprehends all the functions of an advanced scientific calculator including trigonmetric [sic], hyperbolic, logarithmic and exponential functions, powers and roots, linear regression, mean and standard deviation all programmed for easy use. Secondly, it has the ability to store 72 sequential programme steps for automatic repetition of lengthy and complex problems, thereby eliminating the need for re-entering long key sequences, with the consequent likelihood of error. Additionally, it has facilities for branching, skipping, and halting giving you, the user, great flexibility of use and making the PR 100 the ideal machine for all applications. Thirdly, it can be used as a standard calculator with its simple algebraic entry and logic which, coupled with the 10 independent memories and memory arithmetic, makes the PR 100 ideal for the manipulation of numbers in any situation. From the simplest to the most complex problem, the PR 100 offer [sic] high value for money coupled with ease of use which solves all your everyday and specialist calculating needs." I'm not sure on the difference between the first and the third point, and the grammar leaves something to be desired.